Soilcea, an agricultural biotechnology company based in the Tampa area, is using CRISPR gene-editing technology to develop a bacteria-resistant root system for citrus trees. The company's edited rootstock, called Carricea T1, is grafted onto Valencia orange trees and is designed to bolster the tree's natural defenses against the bacteria that cause citrus greening, a disease that can eventually kill infected trees.

The approach targets the part of the plant hit hardest and earliest. "The edited part we have is the rootstock, because that's what's really harmed by citrus greening disease," said Yianni Lagos, Soilcea's president and CEO. "Before you see the first symptom in the fruit or in the top of the tree, 50% of the root system is already dead."

Rather than inserting a new gene, the technology edits existing genes to restore the plant's ability to fight the bacteria. The results, according to Lagos, are dramatic. A typical control tree in the field can harbor roughly 6 million to 7 million copies of the bacteria, while trees on the CRISPR-edited rootstock have shown levels in the thousands — a reduction of more than a thousandfold.

"It's not making it perfectly immune, but a normal tree," Lagos said.

Field comparisons also show striking growth differences. "We have three-year-old trees in the field right now, and it's really night and day," Lagos said. "The trees are growing much, much faster on the CRISPR-edited rootstocks." Some trees have reached twice the size of those planted on control rootstock, he said, while "the controls now are extremely infected."

Beyond disease resistance, the technology could reduce growers' reliance on chemical sprays used to suppress the bacteria — a shift with implications for both farm costs and the environment.

Close to 1 million trees are currently in production using the technology, according to Lagos. Soilcea is now working to mass-produce the rootstock and partner with citrus nurseries across Florida, which would eventually sell the trees once they reach a strong, healthy size.

"Every tree that goes in the ground with the Soilcea rootstock is always going to have that disease-resistant trait, which means we're going to continue to plant more and more throughout Florida," Lagos said. "Over the years, more and more of better-tasting, healthier oranges are going to be hitting the market."

Relief will not be immediate. Lagos said the first large crop using the technology will likely take another three to four years before reaching the market.

For a state whose orange crop has long been an economic and cultural touchstone, the stakes are substantial. Citrus greening has devastated groves across Florida over the past two decades, and growers have cycled through various methods to combat both the disease and damaging freezes with limited success. The EPA's approval of the new tool marks a significant step toward giving Florida citrus trees a better chance at survival — and the industry a chance at recovery.